When officers arrived at the family residence, they found Sherry Ann Blansit's body in the back yard, he said.

Blansit confessed to killing his mother, 45, after they got into an argument over grades, said DeKalb County Sheriff Jimmy Harris.

She died of blunt force trauma, Gregg said, with the weapon being a baseball bat.

Investigators said they found scratches on Blansit, a student at the University of Alabama at Birmingham, when they met him at the scene, CNN affiliate WAFF said.

Mentone is a town of about 500 in northeast Alabama. Blansit's father said his son had been home several weeks and they were waiting for his grades, Gregg said. The father was at work during the day, the chief said.

Tyler Blansit was the couple's only child, Gregg said.

Blansit was charged with murder and is being held in jail, the sheriff said. The DeKalb County Detention Center told CNN late Saturday it was unclear whether he has an attorney.